1. Field of the Invention
The present invention generally relates to a hot-fillable, blow molded plastic container. More particularly, the invention relates to containers of the above variety having a panel section resisting undesirable deformation and operating as both a vacuum panel, to accommodate reductions in product volume during cooling of the hot filled product, and a pinch-grip, for ease of handling.
2. Description of the Prior Art
Hot-fillable plastic containers have become commonplace for the package of products (e.g., juices) which must be filled into the container while hot to provide for adequate sterilization. During filing, the product is typically dispensed into the container while at a temperature of 180.degree. F. and above. Such a container is known as a "hot-fill". After filling, the container is sealed or capped and, as the product cools, a negative internal pressure forms within the sealed container. If not properly designed, the negative internal pressure will cause the container to deform in unacceptable ways, both from an aesthetic and a performance perspective.
Biaxially-oriented polyethylene terephthalate (PET) containers have long been used to receive the hot-filled product with a resulting minimal amount of distortion in the container after cooling. To accommodate the shrinkage and negative internal pressure, the most often employed method is the incorporation of a plurality of recessed vacuum panels into the body portion of the container. The vacuum panels are designed so that as the product cools, they will deform and move inwardly. In one style of container having vacuum panels, the vacuum panels are equidistantly spaced around the body of the container and separated by land portions. A wrap around label is then used to cover all of the vacuum panels and provide the container with an aesthetically pleasing look.
A major problem with containers of the above mentioned vacuum panel design is that they are not easily handled by the end consumer, particularly in 48 oz., 64 oz. and larger varieties.
Plastic containers having specifically designed gripping areas, hereinafter referred to as pinch-grips, were originally seen in containers for "cold-fill" applications. Not being specifically designed for receiving a hot-fill product, those containers, which did not include vacuum panels, could not accommodate the hot-filling procedure or the decrease in internal pressure which occurs in a hot-fill application.
U.S. Pat. Nos. 5,141,120 and 5,141,121, both to Brown et al., are believed to be the first patents which disclose vacuum panels and pinch-grips in combination in a hot-fill container. More particularly, these patents illustrate and describe the incorporation of the vacuum panels and the pinch-grips together into a common vacuum/pinch-grip (VPG) panel of the container.
Since the Brown patents issued, other containers have also adopted the VPG panel construction. Examples of such patents include U.S. Design Pat. No. 334,457 and U.S. Pat. Nos. 5,392,937; 5,472,105 and 5,598,941.
By providing a container with pinch-grips, the use of wrap around labels (as described above) yielded to the use of spot labels in the front and rear of the container. The use of spot labels, however, decreases the overall labeling area of the container. From a bottler's perspective this is undesirable. By combining the pinch-grips and vacuum panels into a common panel as done in the above referenced patents, the front and rear label areas can be provided in such a manner that eliminates the need for vacuum panels beneath the label. Instead of vacuum panels, horizontal stiffening ribs are often provided in these label panels for reinforcement and to ensure that distortion will not occur as a result of the decrease in internal pressure during cooling of the product.
When properly designed, the VPG panels will move inwardly as the container's internal pressure decreases and the product cools. The VPG panels have been seen to generally eliminate significant deformation in the container outside of the VPG panel area as a result of the internal pressures acting upon the container. However, the internal pressure acting on the VPG panels themselves have been seen to cause creases, distortions and other deformations. This is unintended and aesthetically undesirable.
In view of the above and other limitations, it is a primary object of the present invention to provide a VPG panel structure which resists deformation and distortion during filing, cooling and subsequent handling of the container.
Another object of the present invention is to provide a hot-fillable, blow molded plastic container having a VPG panel structure which resists deformation and distortion during filing, cooling and subsequent handling of the container.
A further object of this invention is to provide a container with improved top load characteristics in its shoulder region.
Still another object of this invention is to provide a container with increased labeling capabilities relative to other containers with spot labels.